Telephone system



Get. 20, 1936. E. Pam 2, 7, 9

TELEPHONE SYSTEM 2 Shets-Sheet 1 Filed April 19, 1935 C 1 Mn INVENTOR' ERICH FEIST ATTORNEY.

Oct. 20, 1936. EIFEIST 2,057,890

1 TELEPHOfIE SYSTEM Filed April 19, 1955 2 Sheets-Sheet 2 FIG.2.

IGW

} INVENTOR.

ERIC H F EIST ATTORNEY.

STATES PATENT OFFICE TELEPHONE SYSTEM Erich Feist, Berlin, Germany, assignor to Siemens & Halske Aktiengesellschaft,

Wernerwerk,

Siemensstadt, near Berlin, Germany Application April 19,

1935, Serial No. 17,201

In Germany May 9, 1934 12 Claims.

This invention relates in general to a telephone system having a circuit arrangement for selector switches with several groups of lines in one contact row.

In particular the'invention relates to selector switches with only one direction of motion commonly called rotary switches, and to whose bank contacts several groups of lines are connected, and which are employed as final selectors or group selectors in automatic telephone systems.

In such cases the characterization of groups of lines to be selected presents diiiiculties, for example the .use of differently arranged subscribers numbers, even with a small number of connections entails the use of complicatedswitching and the expenditure of relays.

The invention overcomes these difficulties by providing an arrangement in which the characterization or marking of the desired group'of lines is achieved by the aid of a condenser which is charged over the characterizing contact of the selector reached by a numerical impulse train, and is discharged through a group testing relay on reaching the group contact attached to the corresponding group of lines.

In the following description'the' invention isdescribed by reference "to the embodiment illustrated in the drawings, in which:

Fig. 1 shows an embodiment of the invention in the form of a rotary switch acting as'a final selector, and Fig. 2 an embodiment in the form of a rotary switch acting as a-group selector. Only those parts are illustrated and described which are necessary for the elucidation of the principle of the invention, and to this end certain circuits have not been shown entirely complete.

For the embodiment shown in Fig. 1 an automatic telephone system with forty subscribers is illustrated. The subscribers are assigned the calling numbers 10-49 in the selector bank which are divided into four groups with the numbers 11, 12, 13. 10, 21,22, 23 ..20; 31, 32, 33 ..30 and 41, 42, 143 40, all of the numbers not being indicated. Before each group one of the group contacts I'-G is arranged and at the beginning of the complete bank contact set lie the group marking or characterizing contacts '(the so-called decimal contacts) l-t.

If a subscriber calls another, for'example the subscriber having the callnumber 25 the seizing relay and the impluse receiving relay A energize upon the final selectorLW being seized and these operate their contacts. Corresponding to the number of impluses in the =firstimpluse train transmitted over the subscribers looponoperating the dial over the leads ab, relay A releases and re-energizes the same number of times. Each time a circuit is therefore closed over contact a, the winding of relay V and the contact 60 closed by the seizing of the selector. The rotary magnet D receives current and makes two steps corre sponding to the two impulses transmitted in the first impulse train. The test arm Ac of the selector thus proceeds to contact 2. The line wipers are likewise rotated.

On the first closing of the circuit of the rotary magnet D, relay V energizes and holds during the impulse train. It closes its contact 1c in the circuit of relay X so that the latter is energized. It opens its contact 812 in the circuit of rotary magnet D and of interrupter EU, and opens in preparation its contact 911 in the circuit through resistance W, contact like and the test wiper Ac. Relay X closes its contact I00: in preperation in this circuit, opens its contact H11: in the circuit of rotary magnet D and later closes its contact l-3x in the circuit of auxiliary relay N. This relay energizes over contact I3a: and the contact I20 closed on seizure of the switch by relay C establishes a holding circuit over its contact Mn, and closes its contact l5n in the circuit of the rotary magnet D and the interrupter RU.

After the impulse train has passed, relays V and X release. Relay V closes its contact 91; and through this and the contact Illa: which is still closed, the condenser C2 connected to group characterizing contact 2 is now charged over the following circuit: earth, condenser C2, bank contact 2, test wiper Ac, contacts 912, mm, resistance W and battery. Meanwhile relay X has also deenergized through the opening of its circuit at contact I12 and has broken the circuit just described at its contact War.

On the deenergizing of relay X its contact H X is again closed. Thereupon the rotary magnet D receives current from the interrupter in the following circuit: earth, battery, interrupter RU contacts I572, 812, IBpl and lint, winding of rotary magnet D, and earth, and rotates the wipers of the selector forward until the test wiper Ac reaches the group contact 2, arranged in front of the contacts of the subscribers lines in group 2, which is connected in parallel with contact 2, to condenser C2.

At this time condenser C2 discharges over the following circuit: earth, winding l of relay Pl, the contact l'ld' closed by the rotary motion of the selector, contact 912, test wiper Ac, bank contact 2, condenser C2, earth, and relay Pl energizes. This relay PI is primed through its winding II over the contact I closed by seizure of the switch and holds after the emission of the discharge current from the condenser over this winding II. The circuit of rotary magnet D is opened at contact lfipl and the selector LW is brought to a standstill and is ready for the reception of the second impulse train. Its test wiper rests on group contact 2.

When the second digit 5 of the call number 25 is dialled, the rotary magnet is energized according to the impulses, as has already been described above, in the circuit through contact 5a. of the impulse receiving relay A and the Winding of relay V, and the selector makes 5 steps. Its test wiper thus reaches contact 25.

On the completion of the second impulse train relay V deenergizes again, and tests relay P of the selector LW in the known way. If the desired subscriber is free the test relay energizes in the circuit from earth at contact E80, windings I and II of test relay P, contacts 20p], 91), test wiper Ac, bank contact 25 to battery in the preselector of the called subscriber. On energizing, relay P short circuits its high resistance winding II at its contact Zip, whereby the switch LW is ensured against further seizure in the known way. The ringing current is transmitted to the called subscriber in the usual way until the latter replies and the subscribers can converse together.

If the called subscriber is engaged, the calling subscriber receives the busy signal in the usual way, and the connection is released in the known way on replacement of the receiver.

In the embodiment according to Fig. 2 it is assumed that the rotary switch illustrated is acting as a group selector. The connecting leads leading to the subsequent selectors, e. g., final selectors,are connected to its bank contacts.

The seizure of the group selector IGW occurs in the usual way via the seizing relay C. On being seized the impulse receiving relay A first energizes through both its windings I and II over the subscribers loop leads a and 1). Relay A opens its contact 4a in the circuit of relay V and also the contact 9a in the circuit of rotary magnet D and removes the short circuit of the winding of relay C by opening its contact Ia. Relay C on energizing closes its contact 20 in the circuit of relay V and tile in the circuit of rotary magnet D, and opens in preparation the contact I21) at the contact segment i 3 of the selector. Later it closes its contact l Ic in the circuit of the test relay P and connects its contact 50 to wiper d in position ll,

' On the transmission of the first impulse train on the part of the caning subscriber, for the establishment of the group selector IGW on the desired level or group, group 3, for example, relay K and the rotary magnet D of the group selector are energized on the first impulse.

Relay K energizes in the circuit: earth winding I, c-wiper of the selector in the zero position d-wiper in the zero position working contact to, contact 6a, resistance W, to battery. It closes its contact 7k and holds after the first step of the selector in the circuit: earth, winding I, contact 1k, winding II, battery. At the same time relay K closes its contact 8k in the circuit of the interrupter U.

7 Corresponding to the three impulses in the transmitted impulse train the rotary magnet D is energized and deenergized three times over contacts 9a. and I00 and advances the selector wipers three steps. Wiper 0 thereby reaches the group characterizing contact' 3 to which condenser C3 is attached, and wiper d the contact segment 53 connected to the battery over contact I21). The condenser C3 is charged in the circuit: earth, condenser C3, bank contact 3, selector wiper 0, selector wiper d, contact segment l3, contact I21), resistance Wit, earth.

Relay V holds during the impulse train and releases on the completion of the latter with the opening of the contact 4a. The rotary magnet D now receives current in the circuit: earth, winding of rotary magnet D, contacts 30, i'lp, 8k, interrupter U, battery, and rotates the wipers. The selector hunts freely until the wipers c and it rest on the group contact 3 of the selected third group of lines and by further rotation on contact 2 characterized by a free subsequent final selector.

As a result of wiper c standing on group contact 3 and wiper d on a similarly marked contact 3 the condenser C3 discharges in the circuit: earth, condenser C3, group contact 3' wiper c, wiper d, group contact 3', winding I of group test relay Pl to earth. Relay Pi energizes over its winding I and holds after the termination of the discharge current from the condenser, over its winding II. Relay Pi is held energized through this winding II whose circuit was closed through the energizing of relay K over its contact 63k. Relay Pi closes its contacts Mp and 55p! in the circuit of windings I, II and III of relay P.

On the further rotation of the selector wiper, as soon as the wipers c and d come to rest on a bank contact, for example, bank contact 2 of the third group to which a free trunk or a trunk leading to a free subsequent final selector is attached,

the individual test relay P energizes in a circuit:

earth, winding III of relay A, contact llc, windings I and II of relay P, contact Mp1, contact segment 30, wiper d, wiper 0, bank contact 2 of the third group, and c-lead to the seizing relay and battery in the subsequent final selector. Relay P, through the opening of its contact Hp, interrupts the circuit of rotary magnet D through the interrupter U, and the selector IGW is brought to rest. By the closing of contacts 18p and i921 the aand b-leads are switched through to the group selector IGW.

If the call is switched through to the desired subscriber over the subsequent selector stages, assumed to be the final selector and the subscriber replaces his receiver at the end of the conversation, the release or" the connection results in the known way. In the group selector IGW relay C deenergizes through the opening of the c-lead and thereby also relay P. The rotary magnet D is energized through the interrupter U over the contact I lp again closed, and rotates the selector wiper back into the zero position. Here relay K receives stronger current in the circuit: earth, resistance WiZ, contact 50, wiper d and wiper c in the zero position, contact 170, winding II of relay K, battery. The last Winding opposes winding I, hence relay K deenergizes whereby the holding circuit of relay Pl through its winding II is broken at contact 13k, and. relay Pi also deenergizes whereupon the group selector device attains the rest position.

If the subsequently arranged final selectors reachable over the selected group 3 are all engaged the wipers c and d of the group selector proceed to leave group contact 3 and to rotate further over the dead contacts 3" and to rotate dividual test relay energizes through its windings III in the circuit: earth, winding III of relay A, contact I I0, winding III of relay P, contact i519! contact 3", selector wipers d and 0, contact 3",

busy signal, to battery. At its contact Hp relay P interrupts the circuit of the rotary magnet D and brings the selector-to rest. The busy signal is transmitted to the calling subscriber from the winding I of relay A, through winding III of the latter. The replacement of the receiver by the calling subscriber-results in the release of the connection and the return of the apparatus to the rest position in the same manner as has already been described.

The characterization or bringing to rest of the group selectors on all the succeeding devices constituting a group of lines being engaged, can be brought about in other ways than are'ishown in the embodiment without the overflow contact 3". Thus, for example, a relay can be provided at group contacts l3' which is connected in series with, for example, a working contact of seizing relay C, if all the C relays re-engaged by the engagement of all the outlets of a group, all the C-relays are then energized and their contacts in series with the particular relays are thus closed and these relays are energized. At the group contact of the selected group theindividual test relay is connected through the contact of the auxiliaryrelay and is energized by the discharge current from the condenser. .It interrupts the circuit of rotary magnet through its contact and thereby brings the selector to rest.

It is equally possible to adjust the characterization by the condenser so that for example the characterizing condensers are charged on seizure, are discharged when the selector wiper makes contact with the group characterizing contact, and are recharged when the wiper makes contact with the group contact which may be brought about for example by corresponding alteration of the associated potentials or possibly by adjustment of the contacts.

Having described the invention, what is considered to be new and is desired to be protected by Letters Patent will be set forth in the following claims:

What is claimed is:

1. In a selector switch, a wiper having access to a row of bank contacts, line conductors arranged in groups and connected to corresponding groups of said bank contacts, a group of marking contacts in said bank, a condenser connected to each of said marking contacts, a set of group contacts in said bank also connected to said condensers, means for operating said wiper to engage a marking contact and charge the associated condenser, means for further operating said wiper to engage a group contact and discharge said condenser, and means for finally operating said wiper to select the desired line contact.

2. In a selector switch, a wiper having access to a row of bank contacts, certain of said bank contacts arranged in groups and connected to corresponding line conductors, a group of marking contacts in said row, a condenser connected to each of said marking contacts, a set of group contacts in said bank corresponding to said marking contacts and connected to said same condensers, means for operating said switch in selecting a line conductor to engage said wiper with one of said marking contacts, means responsive to said engagement for charging said condenser in order to mark the group of line conductors in which the desired one is located, means for further operating said switch to engage said wiper with the group contact corresponding to the marking contact to discharge said condenser in order to mark the beginning of the group of desired line contacts, and means for additionally operating said switch to engage said wiper with the bank contact of the desired line in the selected group.

3..A selector switch having a wiper, a row of bank contacts divided into groups and accessible to said wiper, certain of said groups of bank contacts connected to corresponding groups of lines, others of said groups divided into marking contacts, further groups corresponding to said marking contacts divided into group contacts, a condenser connected to each of said marking contacts and the corresponding group contact, means for operatingsaid wiper to connect with any one of said marking contacts and for charging the condenser connected to the same, means for again operating said wiper to connect with the corresponding group contact to discharge the charged condenser, and means for additionally operating said wiper to connect with the bank contact associated with a particular line.

4. A selector switch having a wiper, a row of bank contacts accessible to said wiper, said bank contacts divided into groups comprising, marking contacts, group contacts andline contacts, a condenser connected to each of said marking contacts and multiplied to a corresponding one of said group contacts, lines connected to said line contacts, and means for successively operating said wiper first to one of said marking contacts to charge the associated condenser and mark the group of line contacts to be selected. second to the group contact to discharge the condenser and mark the beginning of the desired group of line contacts, and third to the desired line contact to connect with the line wanted.

5. In a selector switch having a wiper, a row of bank contacts to which said wiper has access, said bank contacts divided into line groups, marking groups, and group contacts, a condenser connected to each of said marking contacts and the corresponding one of said group contacts, means responsive to the reception of a series of impulses for operating said switch to move said wiper into engagement with one of said marking contacts and to charge the associated condenser, means for automatically operating said switch to move said wiper into engagement with the group contact to discharge the charged condenser, and means responsive to the reception of a further series of impulses for operating said switch into engagement with one of said line contacts.

6. In a selector switch having a wiper, a row of bank contacts accessible to said wiper, said bank contacts divided into groups comprising marking contacts, group contacts and line contacts, a condenser connected to each of said marking contacts and a corresponding one of said group contacts, means responsive to the reception of impulses by said switch for operating said wiper in accordance with the impulses to position it into engagement with one of said marking contacts to mark one of the group of line contacts by placing a charge on one of said condensers, means for automatically operating said switch to engage said wiper with the corresponding group contact to mark the beginning of the line group contacts selected by discharging the charged condenser, a test relay connected to said wiper, said test relay energized by the discharge of said condenser, means responsive to the reception of a further series of impulses for operating said switch to position said wiper onto the desired. one of said line contacts, and means controlled by said test relay for testing the busy or idle condition of the line connected to the line contact selected. I i

- 7. In a selector switch as claimed in claim 6 in which the test relay is prepared for operation in a local circuit which aids its energization by the discharge of the condenser, before the automatic operation of the switch.

8. In a group selector switch having a wiper,

bank contacts accessible to said wiper, said bank contacts divided into groups comprising marking contacts, group contacts and trunk contacts leading to final selectors, a separate condenser connected to each of said marking contacts and to a corresponding one of said group contacts, means responsive to the reception of impulses for operating said switch to move said wiper into engagement with a marking contact corresponding to the number of impulses, means responsive to said engagement for placing a charge on the associated condenser to mark a particular group of final selectors, means for then automatically operating said switch to position said wiper onto a group contact to discharge said condenser and mark the beginning of the trunk contact group, a test relay operated by the discharge from said condenser, means for further automatically operating said switch to hunt for an idle one of said trunk contacts in the selected group and means controlled by said test relay to stop the movement of said wiper when it reaches a trunk contact connected to an idle final selector.-

9. In a group selector as claimed in claim 8, means in case all of the trunk contacts of the selected group are busy for stopping the movement of said wiper on thelast contact of the group and transmitting a busy signal.

10. In a selecting switch having a wiper, groups of lines accessible to said Wiper, a pair of group bank contacts for each group of lines, a condenser connected to each pair of group bank contacts, means for directively operating said wiper to one of said group bank contacts, means responsive thereto for charging said condenser to place marking potential on the second group bank contact of the pair thereby marking the corresponding group of lines, means for automatically operating the wiper in search of said second contact having marked potential thereon, means for discharging said condenser in response to the wiper engaging said second contact of the marked group, and means for thereafter operating said wiper to connect with ,a line in the marked group.

11. In a selecting switch having a wiper, groups of lines accessible to said wiper, a group bank contact for each group of lines, a condenser connected to each group bank contact, 'means'for directively operating said wiper to one of said group bank contacts, means responsive thereto for charging the associated condenser to mark the corresponding group of lines, means for automatically operating said wiper in search of the marked group, means for discharging said condenser in response to said wiper finding the marked group, and means for operating said wiper to connect with a line in the marked group.

12. In a selecting switch, groups of lines terminating in said switch, a condenser for each group of lines, means for charging one of said condensers'to mark a corresponding group of lines, means for operating said switch until said condenser is' discharged whereby the marked group is found, and. means for thereafter operating said switch to connect with a line in the marked group.

' ERICI-I FEIST. 

